Ice rink



Dec.- 23, 1969 J. A. ETTER ETAL ICE RINK 5 Sheets-Sheet 1 Filed Dec. 18, 1967 JOSEPH A ETTER MILTON w. GARLAND ATTORNEY J. A. ETTER ETAL Dec. 23

ICE RINK .5 Sheets-Sheet 2 Filed D90. 18, 1967 INVENTORS,

MILTON w. GARLAND \IIIIII w- 23, 1969 J. A. ETI'TER ETAL ICE RINK 5 Sheets-Sheet 5 Filed D90. 18, 1967 INVENTORS, JOSEPH A. ETTER By MILTON W. GARLAND ATTORNEY Dec. 23, 1969 J. A. ETTER ETAL 3,485,057

ICE RINK .5 Sheets-Sheet 4 Filed Dec. 18, 1967 INVENTORS,

JOSEPH A. ETTER' MILTON w. GARLAND AT 'fORNEY United States Patent O 3,485,057 ICE RINK Joseph A. Etter, Cincinnati, Ohio, and Milton W. Garland,

Waynesboro, Pa., assignors to Frick Company, Waynesboro, Pa., a corporation of Pennsylvania Filed Dec. 18, 1967, Ser. No. 691,597 Int. Cl. F25c 3/02; F25b 29/00 US. C]. 62-77 16 Claims ABSTRACT OF THE DISCLOSURE erant through the floor when it is desired to remove the ice from the floor. The refrigerating system may also provide for the passing of heated water from a refrigerant condenser and/or the compressors into a melting pit to melt ice scraped from the floor and collected in the melting pit and returning the cold water from the melting pit to the condenser.

Ice rink This invention relates to refrigerated ice rinks and, more particularly, to ice rinks of the type wherein freezing is achieved by direct circulation of refrigerant in heat exchange pipes located in the floor on which ice is to be formed.

In ice rink construction of the type wherein a secondary fluid, such as brine, ethylene glycol brine, methanol brine or the like, is cooled by a refrigerant and circulated through pipes to freeze the water, or where refrigerant fluid is circulated through pipes to directly effectfreezing of the water, open header trenches have been heretofore required. The disadvantage of this construction in addition to the cost, particularly for indoor installations, is that the header pipes, threaded pipe connections, valve bonnets and stems located in the trenches are exposed to the atmosphere, thereby presenting the danger of injury to persons in the event of leakage of refrigerant from the exposed pipes, fittings and valves. Another disadvantage of present ice rink construction is the difficulty and expensiveness of field fabrication and installation of the heat transfer pipe assemblies of the ice rink floor. A particularly vexing problem is the welding of the pipe sections together because of the requirements for lifting the pipe sections, including the headers, to get more working space than the usual space of about 1% inches between the piping and the ground or whatever its supports rest upon. Maintaining the proper predetermined spaced relationship of the pipes also has proved difiicult and expensive. A still further disadvantage of heretofore known ice rinks, particularly of the direct refrigerant type, is the carry-over of contamination, such as lubricating oil, in the refrigerant fluid into the heat exchange pipe assemblies, which contamination coats the interior of the pipes and reduces thereby heat transfer efficiency.

Accordingly, it is one object of this invention to provide an improved refrigerated ice rink which is of relatively simple construction and inexpensive to install.

Another object of the present invention is to provide an improved refrigerated ice rink wherein the risk of injury to persons in the rink arena due to refrigerant leakage is semblies.

3,485,057 Patented Dec. 23, 1969 "ice substantially less than in conventional ice rink constructions.

A further object of this invention is to provide an improved refrigerated ice rink in which carry-over of entrained contamination in the refrigeration fluid into the heat exchange pipe assemblies is minimized.

A still further objectof the present invention is to provide an improved refrigeration ice rink in which ice scraped from the surface of the floor ice to keep such surface smooth may be simply and economically melted and utilized for cooling and refrigerant condensing.

A further object of this invention is to provide an improved refrigeration ice rink wherein heat losses are minimized and refrigerating power requirements are substantially less than in those ice rink constructions using secondary refrigerants, such as various brine solutions.

A feature of this invention is the pipe spacing and sup port elements which permit quick and easy alignment, spacing and leveling of the heat exchange piping of the ice rink floor.

Another feature of the present invention is a distributor pipe or tube for each heat exchange pipe assembly in place of a conventional orifice plate and the connecting elbow for communicating each heat transfer pipe assembly to the suction and outlet headers, each of which elements can be factory welded to the associated pipe section and field welded to the headers after complete fabrication of the associated heat exchange pipe assembly. This feature also enables the support of the pipe sections to comprise a heat transfer pipe assembly at an elevated position for ease of welding the pipe elements of the section together, since the headers need not also be supported.

A further feature of this invention is the novel combination of refrigeration system components whereby rapid de-icing can be achieved by a reversal of the refrigerant cycle of operation and utilization of waste heat to melt ice periodically scraped from the ice surface to maintain ice surface smoothness.

A still further feature of the present invention is the catch trap associated with the refrigerant inlet header assembly whereby disentrainment and entrapment of contamination in the refrigerant fluid stream is accomplished before it flows into each of the heat transfer pipe as- Another feature worthy of comment is that the heat exchange pipe assemblies and theinlet and outlet headers are completely encased inconcrete or other flooring material to insure non-leakage of refrigerant.

Accordingly, it is contemplated by' the presentinvention to provide an improved ice rink construction which comprises, in combination with a refrigeration system, an ice rink floor comprising one or more heat exchange pipe assemblies or banks connected to receive refrigerant from an inlet header means communicating with the refrigeration system and to discharge heated refrigerant into a suction or outlet header communicating with the refrigeration system for recirculation through the latter. A contamination trap means is associated with the inlet header means to disentrain and trap solid and liquid contamination entrained in the refrigerant beforeit flows into the heat transfer pipe assemblies. Each of the heat transfer pipe assemblies has a distribution pipe or tube for conducting refrigerant from the inlet header means to the associated heat transfer pipe bank. Each of thedistribution pipes is of substantially reduced flow area to restrict refrigerant flow and, thereby, insure substantially equal flow of refrigerant through each of the heat exchange pipe assemblies; Connecting means is provided for communicating each of the heat exchange pipe assemblies with the outlet or suction header. Pipe spacing and support elements are positioned in engagement with the pipes of the heat exchange pipe assemblies and in spaced relation to each other to support the pipes in a predetermined spaced relationship to each other and the ground and maintain that relationship while the floor material, such as concrete, is poured. The heat exchange pipe assemblies and the inlet header means and outlet header, which may be first pressure tested for leakage, are encased in the floor material, thereby sealing the entire assembly into a unitary structure and reducing the risk of refrigerant leakage to a negligible factor.

The refrigeration system comprises a compressor connected to receive gaseous refrigerant from an accumulator and discharge compressed refrigerant to a condenser in which the refrigerant is condensed and passed to the accumulator. The liquid refrigerant is pumped from the accumulator to the inlet header means.

To provide for rapid de-icing by reversal of the refrigerant flow, the refrigeration system may be provided with a conduit and valve means for bypassing the hot compressed refrigerant, discharging from the compressor, around the condenser and accumulator and delivering the same directly to the outlet header, while return piping and suitable valving is provided for receiving refrigerant from the inlet header means and passing the same to the condenser for absorption of heat and thence to the accumulator.

The refrigeration system may, also, include an ice melting pit connected to the water jackets of the compressor and the condenser to circulate the water therebetween and, thereby, utilize the heat generated by the compressor and heat removed in condensing the refrigerant to melt the ice held in the melting pit, and return cold water to the compressor and condenser for further heat removal.

The heretofore set forth objectives and advantages of the present invention will appear more fully hereinafter from a consideration of the detailed description which follows when taken together with the accompanying drawings wherein one embodiment of the invention is illustrated by way of example, and in which:

FIG. 1 is a plan view of the heat exchange piping for the floor of the ice rink, according to the present invention; with parts broken away for illustration purposes;

FIG. 2 is a cross sectional view taken substantially along line 22 of FIG. 1;

FIG. 3 is a fragmentary enlarged view taken substantially along line 33 of FIG. 1;

FIG. 4 is a fragmentary enlarged cross sectional view taken substantially along line 4-4 of FIG. 1;

FIG. 5 is a somewhat schematic view, similar to FIG. 2, showing how fabrication of the heat exchange pipe as semblies, according to this invention, may be achieved without lifting the header elements;

FIG. 6 is a fragmentary enlarged cross sectional view taken substantially along line 6-6 of FIG. 5 showing a pipe spacing and support element according to this invention; and

FIG. 7 is a schematic diagram showing the refrigeration system forming part of this invention.

Now referring to the drawings, wherein the novel ice rink construction according to this invention is illustrated, reference number 10 generally designates the novel ice rink floor shown in FIGS. 1 to 6 and number 11 generally identifies the refrigeration system shown in FIG. 7.

Ice rink floor The ice rink floor 10, as best shown in FIGS. 1 and 2, comprises a plurality of heat exchange pipe assemblies 12 arranged in side by side relationship and supported in a horizontal plane on a ground surface 13 which has been leveled to receive the floor. While only two assemblies 12 are shown in FIG. 1, it is to be understood that more than two assemblies may be provided, the number of assemblies 12 being d pendent upon the s ze of the ice 4 rink desired. Each of the assemblies 12 has a plurality of straight, spaced, parallel portions interconnected by return bend portions 14 so as to provide flow of fluid serially through the straight portions. Because the length of each straight portion may be relatively great, such as feet, depending upon the size of the ice rink, each straight portion is constructed of a plurality of pipe sections 15 secured in end to end relationship, as for example by butt welding as at 16, and secured, as by welding, to return bend portions 14 and terminal straight portions, specifically inlet pipe 17 and outlet pipe 18.

Below each of the heat exchange assemblies 12 is disposed an inlet header assembly 19 and an outlet header 20- located in a shallow trench 21 in the ground and resting on spaced, horizontal supports 22. The inlet header assembly 19 communicates with a refrigerant feed line or pipe 23 for receiving liquid refrigerant from refrigerating system 11, while outlet header 20 communicates with a refrigerant return line or pipe 24 to return refrigerant fluid to the refrigerating system 11.

Inlet header assembly 19 comprises a main pipe 25 which is connected, at one end, to feed pipe 23 and, at the opposite end, terminates in a trap 26. Trap 26 consists of an elongated cylinder, which is closed at the opposite end from the connection with pipe 25 to form a relatively large trap chamber. Disposed in spaced parallel relationship with main pipe 25 is a distribution manifold 27. Manifold 27 is connected to receive refrigerant from trap 26 by a connecting pipe 28 which extends normal to the longitudinal axis of pipe 25 and communicates at the lateral portion of the trap chamber. Since the refrigerant flow is required to change direction to enter and flow through pipe 28, entrained deleterious matter, such as oil and solid particles, are disentrained or thrown out of the fluid stream by centrifugal action and trapped in trap 26. The refrigerant, by action of trap 26, flows into the distributor manifold with negligible entrainment of deleterious matter.

As best shown in FIG. 4, each of the heat exchange assemblies 12 is connected to distribution manifold 27 by a distributor pipe 29. The distributor pipe 29 is disposed to extend vertically between distribution manifold 27 and inlet pipe 17 and is secured, as by welding, to distribution manifold 27 and inlet pipe 17. Distributor pipe 29 is provided with a relatively small axial bore 30 to restrict the flow of refrigerant and, thereby, insure substantially uniform distribution of refrigerant flow to each of the heat exchange assemblies 12. As best shown in FIG. 3, outlet pipe 18 of each of the heat exchange assemblies 12 is connected to outlet header 20 by an elbow 31 to pass refrigerant fluid, from the associated heat exchange assembly 12, to the outlet header.

In the fabrication or installation of floor 10, it is necessary to allow for slight variations in pipe lengths and header alignment to accurately position assemblies 12. Accordingly, inlet pipe 17, outlet pipe 18 and return bend portions 14 are of slightly larger diameter than pipe sections 15 so that the latter elements are slidably receivable in the open ends of pipes 17 and 18 and return bend portions 14. The outside diameter of pipe sections 15 in relation to the inside diameter of the mating pipe element is such that there is a snug fit between overlapping pipes and minimal lateral relative movement. In addition to allowing for varying lengths, the telescoping or overlapping relationship of the pipes to be welded together minimizes the possibility of welding dirt, such as metal particles and/or flux, being introduced into the interior of the piping and, thereby, reduce heat transfer efliciency of the assembly or cause other detrimental effects.

As illustrated in phantom lines in FIG. 5, the pipe sections 15, return bend portions 14, inlet pipe 17 and outlet pipe 18 of assemblies 12, may be supported on one or more saw horses 32 or other device for elevating the pipe sections to provide the necessary convenient working space to Weld the various pipe elements in o a unitary heat exchange assembly 12. Also to facilitate field fabrication of assemblies 12, the distributor pipe 29 and elbow 31 may be welded to inlet pipe 17 and outlet pipe 18, respectively, at the factory or in the field, before securing the inlet pipe and the outlet pipe to their associated pipe section 15. After the complete fabrication of each assembly 12, it can be lowered on to spaces and support elements 33 and one or more pier elements 34 and positioned so that the distal ends of distributor pipe 29 and elbow 31 register with complementary openings in distribution manifold 27 and outlet header 20, respectively. Thereafter, the distributor pipe 29 and elbow 31 are welded to the distributor manifold and the outlet header.

As is best shown in FIG. 6, each of the spacer and support element 33 comprises a metal plate folded back upon itself at 35 (FIG. 5) to form a base portion 36 and an inclined upwardly projecting portion 37, the latter portion being folded to provide a vertical portion 38. Vertical portion 38 is provided along its upper edge with a plurality of spaced V-shaped notches 39 corresponding in number to the number of pipe sections 15 to be supported. The notches 39 are spaced apart the distance it is desired to space pipe sections 15 from each other and dimensioned to receive a pipe section 15 therein.

Each of the pier elements 34 comprises a metal plate folded back on itself to form a base portion 40 and an upwardly inclined portion 41. Each of the pier elements 34 has a planar top edge 42 and is dimensioned to support, in cooperation with spacer and support elements 33, the pipe elements 15 of the heat exchange assemblies 12 at a predetermined distance from the ground surface 13.

After all of the heat exchange assemblies 12 are properly fabricated, aligned and connected to inlet header assembly 19 and outlet header 20 and tested for tightness of joints, the entire assembly is encased in a floor material, such as poured concrete, to form a floor slab 43. The spacer and support elements 33, and piers 34 function to maintain the proper alignment and spacing of the pipe sections 15 of the assemblies 12, from each other and the ground, during the floor pouring operation. Since the assemblies 12, the inlet header assembly 19 and outlet header 20 are completely sealed in the floor slab 43, leakage of refrigerant fluid from defective pipes, joints, or accidental damage to the floor piping resulting in leakage, is obviated, thus reducing the risk of injury to persons to a negligible value.

Refrigeration system To provide for circulation of refrigerant fluid, such as ammonia, Freon or R-22, through the floor 10, a refrigeration system recirculates refrigerant into the floor via feed pipe 23 and back to the refrigeration system via return pipe 24. As shown in FIG. 7, the refrigeration system comprises a compressor 50 which is connected, through a suction pipe 51, to receive gaseous refrigerant from an accumulator 52. The compressed gaseous refrigerant is discharged via a discharge pipe 53 into an oil-refrigerant separator 54, wherein oil entrained in the compressed fluid is removed, and returned to the com pressor via pipe 55. The compressed refrigerant is conducted, from the oil-refrigerant separator 54, by the pipe 56 to a condenser 57. The condenser 57 may be of the evaporative type located outdoors and having heat transfer tube banks or coil in which refrigerant is condensed and over which atmospheric air is passed while the surface of the tubes or coil 57A are externally wetted by water. A check valve 58 and a flow control valve 59 are disposed in pipe 56. The check valve 58 prevents back flow of fluid in line 56 toward the oil separator 54. From condenser 57, liquid refrigerant is conducted by a pipe 60 to the liquid reservoir of accumulator 52. To control flow of fluid through pipe 60, a normally open valve 62 is disposed in pipe 60 to allow the liquid refrigerant to flow, via pipe 60, into and through a float trap 64. The float trap 64 functions to pass only liquid refrigerant and at substantially the pressure of fluid in accumulator 52.

A check valve 65 is disposed in pipe 60 to prevent fluid flow in pipe 60 toward float trap 64. From the sump leg 66 of accumulator 52, the liquid refrigerant is withdrawn by pump 67 into supply or feed pipe 23 and delivered by the latter to floor 10. After the liquid refrigerant absorbs heat from the concrete slab 43 and the water thereon to freeze the latter in flowing through heat exchange pipe 12 of floor 10, the heated refrigerant, which may be a mixture of liquid and gaseous refrigerant, is conducted by return pipe 24 to accumulator 52. A valve 68 is disposed in return pipe 24 for controlling flow of refrigerant therethrough. In accumulator 52, the liquid and gaseous refrigerant is separated, and the separated gaseous refrigerant held in dome 69 of the accumulator, from Where it is Withdrawn to compressor 50, via suction pipe 51. The accumulator 52 is provided with a liquid level control system 70.

De-icing system To provide according to this invention for rapid de-icing of the floor 10, the refrigeration system 11 includes a bypass pipe 71 communicating, at one end, with pipe 56 between the check valve 58 and flow control valve 59 and, at the opposite end, with return pipe 24 on the side of the valve 68 opposite from accumulator 52. Bypass pipe 71 has a flow control valve 72 to control flow of hot compressed gaseous refrigerant, through the pipe, to return pipe 24. A reverse cycle return pipe 73 is connected, at one end, to feed pipe 23 and, at the opposite end, to pipe 56, downstream from flow control valve 59, to conduct refrigerant fluid from floor 10 during the de-icing cycle of operation. A pipe 75 communicating, at one end, with pipe 73 and pipe 56 and, at the opposite end, with pipe 60 is provided to connect the condenser 57 with the accumulator 52 so that normally trapped hot gaseous refrigerant in the condenser is passed to the accumulator, when valve 94 in pipe 75 is open, to thereby obtain the benefits of the heat in the gaseous refrigerant in the defrosting cycle of operation. Flow control valve 93 is provided in pipe 73 to control flow of fluid through the pipe. A pipe 100, having a flow control valve 96, is connected to communicate at opposite ends with pipes 60 and 73. Communicating pipe 100 with pipe 75 is a pipe 101. A pipe 102 is in communication with return pipe 73 and pipe 101. A pressure regulating valve 76 is disposed in pipe 102, which valve is preset to open and pass refrigerant to condenser 57 at a predetermined pressure in return pipe 73 equal to a pressure corresponding to a temperature above 32 R, such as 81.4 p.s.i.g. which is 54 F. when the refrigerant is ammonia. A flow control valve 95 is disposed in pipe 73 between the junctures of pipes and 102 with return pipe 73. A flow control valve 97 is positioned in pipe 101 between the connecting points of pipes 100 and 102 with pipe 101. Another flow control valve 98 is disposed in pipe 101 on the opposite side of the juncture between pipes 102 and 101 from valve 97.

As hereinafter more fully described, compressor 50 may be cooled by circulating a portion of the water from a melting pit 80, via Water circulation pump 84 and pipes 82, 83 and 87, to the compressor. To provide cooling water for the compressor when water circulation pump 84 is not operating, a pipe 105, having a flow control valve 99, is connected, at one end to pipe 87 and, at the opposite end to a make-up water supply pipe 85. A flow control valve 107 is disposed in pipe 106. By opening valve 99 and closing valve 107, cooling water is permitted to flow from a suitable source thereof (not shown), through pipes 85, and 87 to compressor 50, the heated cooling Water flowing from the compressor via pipe 88. A check valve 108 is disposed in pipe 87 to insure flow of water in pipe 87 toward compressor 50.

The defrost or de-icing portion of refrigerating system 11 above described provides two alternative defrost or de-icing systems. One defrost system may be employed Where outside weather conditions permit the evaporative condenser to function as an air heat exchanger to extract from the outside air the necessary B.t.u.s of heat for loosening the ice from the surface of floor 10, hereinafter referred to as air defrost system. The other alternate defrost system may be employed where sutficient heat cannot be quickly extracted from the atmospheric air and the relatively warm water in condensing pit 80 is circulated through the condenser to provide the necessary B.t.u.s of heat required to loosen the ice from the ice rink floor 10, hereinafter referred to as the water defrost system. I

In operation of the air defrost system of the refrigerant system 11, valves 59, 62,68, 93, 96 and 98 in pipes 56, 60,

24, 73, 100 and 101, respectively, are closed while valves 72, 94, 95 and 97 in pipes 71, 75, 73 and 101, respectively,

are open. In addition, refrigerant circulation pump 67 and a condenser water circulation pump 84, hereinafter described, are shut off. With pump 84 shut off, valve 99 in pipe 105is opened and valve 107 in pipe 85 is closed so that compressor cooling water flows from suitable source of cold water, such as city water, via supply pipe 85, pipe 105 and pipe 87, and thence to compressor 50. Also, at this time, the condenser fan (not shown) is operated to draw or force atmospheric air through coil 57A of condenser 57. With valves adjusted, as previously described, and compressor 50 operating, gaseous refrigerant is withdrawn via suction pipe 51, by the compressor and discharged compressed, through pipe 53, into oil separator 54. From separator 54, the hot compressed refrigerant gas is conducted, via pipe 56, to and through bypass pipe 71, into return pipe 24. From return pipe 24 the high pressure, hot gaseous refrigerant flows into outlet header 20 and, thence through heat exchange assemblies 12. Since the hot gaseous refrigerant is discharged directly into the heat exchange assemblies, it is at a higher pressure than the liquid and/or gaseous refrigerant in the heat exchange assemblies 12 and, therefore, displaces the liquid and/or gaseous refrigerant left in the pipes at the start of the defrost .or de-icing cycle of operation. From each of the heat exchange assemblies, the hot gaseous refrigerant flows, through distributor pipes 29, into inlet header assemblies 19 and, thence to feed pipe 23. In flow through the heat exchange assemblies, the hot gaseous refrigerant loses heat to the floor and ice thereon, thereby loosening the ice from the floor surface. Also, at the same time, at least some of the gaseous refrigerant is condensed in the heat exchange assemblies. From feed pipe 23, the gaseous and/ or liquid refrigerant flows, through pipe 73, into pipe 102. When pressure regulating valve 76 opens, under a predetermined pressure in pipe 73, refrigerant flows through pipe 102 into pipe 101. Since valve 98 in pipe 101 is closed and valve 97 is open, the refrigerant flows, through pipe 101, into pipe 100. With valves 62 and 96 closed, the refrigerant flows from pipe 100 into and, through pipe 60, to the condenser coil 57A of condenser 57. The refrigerant, in flowing through the condenser coil, absorbs heat from the air flowing between the coil elements. If it is assumed that the pressure regulating valve 76 is preset to provide pressure of 75 p.s.i.a. onthe refrigerant in the rink floor 10, heat then can be extracted from the air at a temperature as low as R, which is equivalent to -40 F. of ammonia. From the condenser coil 57A the heated refrigerant flows into pipe 56 and, thence, through pipe 75, to accumulator 52. From accumulator 52, the gaseous refrigerant is drawn through suction pipe 51 into compressor 50 for recirculation through the system. I

In the event atmospheric air temperature, at the time it is desired to remove the ice from the ice rink floor, is

below 32 F. the water defrost system may be employed. In operation of the water defrost system, valves 59, 62, 68, 94, 95 and 97 in pipes 56, 60, 24, 75, 73 and 101, respectively, are closed while valves 72, 93, 96 and 98 in pipes 71, 73, 100 and 101, respectively, are open. The refrigerant circulating pump 67 and the fan (not shown) of condenser 57 are not operated, while a water recirculation pump 84 may be operated to deliver water from a snow melting pit 80 to condenser 57 wherein the water is discharged to externally wet the coil. With compressor 50 operating, compressed, hot, gaseous refrigerant bypasses accumulator 50 and is circulated through heat exchange assemblies 12 of floor 10 to heat the latter and loosen the ice for removal as previously dsecribed. The cooled.and,.at least partially condensed refrigerant flows from the heat exchange assemblies through feed pipe 23 and thence into pipe 73. Since valve 95 in pipe 73 is closed and valve 96 is open, the refrigerant flows from pipe 73 into. and through pipe 100. From pipe 100, the refrigerant flows into pipe 60 and thence, into the coil 57A of condenser 57. The refrigerant then flows into pipe 56, from coil 57A, and, since valves 59 and 94 are closed, into pipe 73 and past open valve 93. From pipe 73, the refrigerant flows into pipe 102 and, if the pressure in pipe 73 and V 102 is at the value for which pressure regulating valve 76 is preset, the refrigerant flows from pipe 102 into pipe 101. Since valve 97 is closed and valve 98 is open, the refrigerant flows through pipe 101 into pipe 75 and, from pipe 75,

- into accumulator 52. The gaseous refrigerant is then drawn oh? the accumulator 52, through suction pipe 51, and conducted to compressor 50 for recompression and recirculation through floor 10.

The pressure regulating valve 76, in addition to maintaining refrigerant pressure in floor 10 at a predetermined value, also functions to impose on the compressor 50 an artificial'load to obtain thereby maximum heat input from the compressor. This load is achieved because the setting of valve 76 raises the refrigerant pressure in floor 10 to a level corresponding to a temperature above 32 F., for example 54 F.

Both the air and water defrost system effect a conservation of the heat energy by recovering the heat in the hot gaseous refrigerant which is in the condenser at the time of switching the refrigerating system from the freezing cycle of operation to the de-icing cycle of operation and the heat which may be in the air or in the water circulated through condenser 57.

Condensing and cooling water system The refrigeration system 11 may also include another means for providing an efficient refrigerating system. This heat conservation means comprises a snow melting pit 80 disposed, in any convenient location, to receive the ice scraped from the surface of the ice covering floor 10. This ice accumulated in the pit is melted by delivery of heated water, from condenser 57, to pit 80, through pipe 81. The melted ice and cooled condenser water is circulated to condenser 57, by way of pipes 82 and 83, and pump 84, to effect further condensing of refrigerant flowing through condenser 57. Make-up water is supplied to pit 80 by way of supply pipe 85, which supply is controlled as required by a float control valve 86 in pipe 85. In addition, to utilizing the water in pit 80 for condensing, part of the water may be utilized to effect cooling of compressor 50. Tocool compressor 50, pipe 87 is connected, at one end, to pipe 83 to receive cold water and, at the other end, to the water jackets of compressor 50 to deliver the cold water to the latter. A return tube or pipe 88 is connected to the compressor to receive heated water, from the water jacket, and deliver the heated water to pit 80 for melting ice. The pit 80 is provided with an overflow pipe 89 and drain pipe 90 which are connected to a main drain pipe 91, the latter being in communication with a sewer. A drain valve 92 is disposed in drain pipe 90 to control flow through the pipe. ,As previously described in operation of the air defrost system, cooling of compressor 50 may be provided by opening valve 99 in pipe and closing valve 107 in pipe 85. This valve adjustment permits cold water from a suitable source thereof to flow, through pipes 85, 105 and 87, to compressor 50, the heated water flowing from compressor 50 to pit 80 via pipe 88.

Operation of refrigeration system In the freezing cycle of operation of refrigeration system 11, valves 72, 93, 94, 95, 96, 97 and 98 in pipes 71, 73, 75, 73, 100, 101 and 101, respectively, are closed while valves 62, 68 and 59 in pipes 60, 24 and 56, respectively, are open. The compressor 50 is on and operating, as is circulation pump 67. If the compressor 50 is cooled by water from pit 80, valve 99 in pipe 105 is closed and valve 107 in pipe 85 is open. Water circulation pump 84 is operating to supply cold water to condenser, 57, via pipes 82 and 83, as well as cooling water to the compressor via pipe 87. Under these conditions, gaseous refrigerant flows, from dome 69 of accumulator 52, to compressor 50 by way of pipe 51. The hot, compressed, gaseous refrigerant is discharged from compressor 50, into an oil separator 54 where oil and refrigerant are separated. The separated oil is returned by pipe 55 to the compressor for further lubrication work while the separated gaseous refrigerant flows, from the oil separator, via pipe 56, to condense 57 where the refrigerant passes in indirect heat exchange relationship with cold water delivered to the condenser by pipes 82 and 83, from a suitable source, such as pit 80. The heated water is discharged from condenser 57, through pipe 81, to a suitable place, such as pit 80. The condensate or liquid refrigerant flows by way of pipe 60, from condenser 57, to float trap 64. From float trap 64, the refrigerant liquid free of any entrained gaseous refrigerant is delivered to accumulator 52. From sump 66 of accumulator 52, liquid refrigerant is forced by pump 67, through feed pipe 23, to inlet header assembly 19. From distribution manifold 27 of assembly 19, liquid refrigerant flows, through distributor pipe 29, to each of a plurality of heat exchange assemblies 12. In flowing through each of the assemblies 12, the liquid refrigerant absorbs heat from concrete floor slab 43 and the water applied to the surface of the slab 43 to cause the water to freeze. In absorbing heat, at least some of the refrigerant is vaporized, and this refrigerant fluid discharges into outlet header 20 and, thence, into return pipe 24 and accumulator 52. In accumulator 52, gaseous refrigerant separates from the liquid refrigerant and is trapped in dome 69, while the liquid refrigerant, if any, passes to the liquid reservoir and sump 66 along with liquid refrigerant delivered to accumulator 52 by pipe 60.

It is believed now readily apparent that the invention, herein disclosed, provides an improved refrigerated ice rink construction, the floor of which can be quickly and easily installed, and where the danger of injury to persons due to leakage of refrigerant from the floor heat exchange assemblies is negligible. It is an improved ice rink construction in which the refrigerating system is of high efliciency, and where the refrigerant flow can be quickly and easily reversed to provide for rapid de-icing of the ice covering the floor. Furthermore, the refrigerating system is more eflicient than heretofore known systems by utilizing the heated water from the refrigerant condenser to dispose of scraped floor ice and the resultant cold water used to achieve additional refrigerant condensing and/or compressor cooling.

Although but one embodiment of the invention has been illustrated and described in detail, it isto be expressly understood that the invention is not limited thereto. Various changes can be made in the arrangement of parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

1. An ice rink floor on which ice is to be formed in combination with refrigerant liquefying means compris- (a) an inlet header means connected to receive refrigerating fluid from said refrigerant liquefying means,

, (b) an outlet header means connected to pass refrigerating fluid to the refrigerant liquefying means, (0) a plurality of heat exchange pipe assemblies each including pipes arranged in a serpentine pattern and in a substantially horizontal plane,

(d) each of said heat exchange pipe assemblies being of predetermined minimum diameter and having a connecting pipe with a maximum diameter substantially less than the diameter of said heat exchange pipe assemblies defining a restricted. flow area for communicating said heat exchange pipe assemblies with the inlet header means to conduct refrigerant fluid from said inlet header means to each assembly,

(e) means connecting each of said heat exchange assemblies to said outlet header means to discharge refrigerant fluid from said assemblies,

(f) floor means providing a support surface for the water to be frozen, and

(g) said heat exchange pipe assemblies being encased within said floor means and in heat exchange relationship therewith.

2. The apparatus of claim 1 wherein said inlet header means includes a trap means for disentraining and trapping contamination entrained in the refrigerant fluid flowing in the inlet header means.

3. The apparatus of claim 1 wherein said inlet header means comprises (1) an inlet pipe communicating at one end to receive refrigerant fluid from the refrigerant system, and at the opposite end with an element defining an enlarged chamber,

(2) a pipe means disposed adjacent said inlet pipe and communicating with the enlarged chamber substantially normal to the direction of fluid flow through the inlet pipe to cause change in the direction of fluid flow and thereby the disentrainment of contamination and retention of the same in the enlarged chamber,

(3) said pipe means communicating with said connecting pipe to provide for flow of refrigerant fluid to the latter.

4. An ice rink floor on which ice is to be formed in combination with refrigerant liquefying means compris- (a) an inlet header means connected to receive refrigerating fluid from said refrigerant liquefying means,

(b) an outlet header means, connected to pass refrigerating fluid to said refrigerant liquefying means,

(c) at least one heat exchange pipe assembly comprising a plurality of refrigerant conducting pipes disposed in a substantially horizontal plane,

(d) means for connecting the heat exchange pipe assembly to the inlet header means to receive refrigerant from the latter and for passing refrigerant from the heat exchange pipe assembly to the outlet header means,

(c) said inlet header means including trap means for disentraining and trapping contamination entrained in the refrigerant fluid delivered to the inlet header means,

(f) floor means disposed in heat exchange relationship with the heat exchange pipe assembly to provide a support surface for the water to be frozen, and

(g) said inlet header means including a distribution manifold, a conduit adjacent said distribution manifold and communicating at one end with the refrigerating means and at the opposite end communicating with the trap means and a conduit means laterally extending from the trap means to the distribution manifold so that the refrigerant fluid stream in said trap means is caused to change direction and thereby disentrain contamination carried in the refrigerant fluid stream and trap the contamination.

5. The apparatus of claim 1 wherein each of said heat exchange pipe assemblies comprises a plurality of spaced,

substantially parallel, straight pipe sections and U-bend pipe SeCtiOns interconnecting opposite adjacent end of the straight pipe sections to provide for series flow of refrigerant fluid through the pipe sections, the straight pipe sections and U-bend pipe sections being of different diameters so that the end of one pipe section is receivable in the end of the other pipe section so that the overlapping end portions may be Welded together in a fluid tight manner.

6. The method of constructing an ice rink floor comprising the steps of (a) leveling the ground to receive the floor,

(b) excavating a shallow trench along one side of the leveled ground,

(c) positioning an inlet header assembly and an outlet header assembly in the trench,

(d) connecting the inlet headerassembly to a refrigerating apparatus so as to receive refrigerant from the refrigerating apparatus and connecting the outlet header to the refrigerating apparatus so as to pass refrigerant fluid to the latter,

(e) interconnecting the pipe sections of a heat exchange pipe assembly in such a manner as to provide series flow of fluid in a sinuous flow path through the pipe sections,

(f) supporting the pipe sections of the heat exchange pipe assembly during assembly of the latter above the leveled ground a distance sufficient to facilitate joining of the pipe sections to each other,

(g) securing a depending distributor pipe at one end to one of the terminal pipe sections of the heat exchange assembly and an outlet connecting pipe at one end to the other of the terminal pipe sections of the heat exchange assembly,

(h) lowering the assembled heat exchange pipe assembly to the leveled ground and with the depending distributor pipe and outlet connecting pipe in registry with the openings in the inlet header assembly and the outlet header assembly, respectively, and

(i) securing the distributor pipe and outlet connecting pipe in their associated openings in the inlet and outlet header assemblies.

7. In the method of claim 6, the additional step of encasing the interconnected heat exchange pipe assembly and the inlet and outlet header assemblies in a poured floor material to form a fluid tight, unitary assembly.

8. In the method of claim 6, the step of supporting the pipe sections of the heat exchange pipe assembly in a predetermined spaced relationship to each other and the surface of the leveled ground.

9. In a refrigerated ice rink construction having a floor on which ice is to be formed and in which floor a heat exchange conduit bank is associated, the combination of a refrigerating system comprising (a) accumulator means for providing a reservoir of liquid refrigerant and a space for collecting gaseous refrigerant,

(b) compressor means connected to receive gaseous refrigerant from the accumulator means and to compress the same,

(c) a condenser connected to receive gaseous refrigerant from the compressor means and to condense the compressed gaseous refrigerant,

(d) first conduit means for communicating the condenser with the accumulator means to conduct liquid refrigerant to the liquid reservoir of the accumulator means,

(e) second conduit means for circulating liquid refrigerant from the accumulator means to the heat exchange conduit bank and back to the accumulator means, and

(f) defrosting means for conducting hot gaseous refrigerant from the compressor means through the second conduit means into and through the heat exchange conduit bank and to the accumulator means 12 in a direction of flow opposite from the normal direction of refrigerant flow when it is desired to heat the floor to facilitate removal of ice from the floor. 10. The apparatus of claim 9 wherein said defrosting means includes means for flowing uncondensed gaseous refrigerant from the condenser to the accumulator.

11. The apparatus of claim 9 wherein a snow melting pit is disposed to receive ice scraped from the floor and is connected to the condenser to receive Warm c ondsensing Water to melt the ice and return cold water to the condenser for condensing further quantities of refrigerant 12. The apparatus of claim 9 wherein a snow melting pit is disposed to receive ice scraped from the floor and connected to the compressor means to receive heated water for melting the ice and returning cold Water to the compressor means for cooling the latter.

13. In a refrigerated ice rink construction having a floor on whichice is to be formed and with which floor a heat exchange bank is'associated, the combination of a refrigeration system comprising I (a) an accumulator for providing a reservoir of liquid refrigerant and a spacefor collecting gaseous'refrigerant, Y

(b) a compressor connected to receive gaseous refrigerant from the accumulator and to compress the same,

(0) a condenser connected to receive gaseous refrigerant from said compressor to condense the refrigerant,

(d) first conduit means for communicating the condenser with the accumulator to conduct liquid refrigerant to the liquid reservoir of the accumulator,

(e) second conduit means connected to the accumulator and said heat exchange bank associated with the floor to conduct liquid refrigerant to the latter from the accumulator,

(f) return conduit means connected to the heat exchange bank and to the accumulator to conduct heated refrigerant fluid to the accumulator where gaseous and liquid refrigerant are collected,

(g) a bypass conduit connected to communicate the compressor discharge with the return conduit means,

(h) third conduit means communicating the second conduit means with the accumulator to conduct refrigerant fluid to the latter, and

(i) control valve means for providing in one condition of operation the stopping of flow of refrigerant from the compressor to the condenser and accumulator and allowing flow of hot gaseous refrigerant through the bypass conduit, return conduit means, heat exchange bank, second conduit means and third conduit means for heating said floor to facilitate the removal of the ice from the floor.

14. In a refrigerated ice rink construction having a floor on which ice is to be formed and with which floor a heat exchange conduit bank is associated, the combination of a refrigerating system comprising (a) accumulator means for providing a reservoir ,of liquid refrigerant and a space for collecting gaseous refrigerant,

(b) compressor means connected to receive gaseous refrigerant from the accumulator means and to compress the same, i

(c) a condenser connected to receive gaseous refrigerant from the compressor means and to condense the compressed gaseous refrigerant, V

(d) first conduit means for communicating the condenser with the accumulator means to conduct liquid refrigerant to the liquid reservoir of the accumulator means,

(e) second conduit means for circulating liquid refrigerant from the accumulator means to the heatexchange conduit bank and back to the accumulator means, and 1 (f) a snow melting pit disposed to receive ice scraped from the floor and connected to the compressor means to receive heated cooling Water for melting the ice and returning cold water to the compressor means for cooling the latter.

15. In a refrigerated ice rink construction having a floor on which ice is to be formed and with which floor a heat exchange conduit bank is associated, the combination of a refrigerating system comprising (a) accumulator means for providing a reservoir of liquid refrigerant and a space for collecting gaseous refrigerant,

(b) compressor means connected to receive gaseous refrigerant from the accumulator means and to compress the same,

(c) a condenser connected to receive gaseous refrigerant from the compressor means and to condense the compressed gaseous refrigerant,

(d) first conduit means for communicating the condenser with the accumulator means to conduct liquid refrigerant to the liquid reservoir of the accumulator means,

(e) second conduit means for circulating liquid refrigerant from the accumulator means to the heat exchange conduit bank and back to the accumulator means, and

(f) a snow melting pit disposed to receive ice scraped from the floor and eonnected to the condenser to receive warm condensing water to melt the ice and return cold water to the condenser for condensing further quantities of refrigerant fluid.

16. The combination of a refrigerated ice rink floor for freezing ice thereon, a melting pit for melting ice scraped from the surface of the ice on said floor, and a refrigerant liquefying means, said ice rink floor including an inlet header means for receiving refrigerating fluid from said refrigerant liquefying means, an outlet header means for passing refrigerating fluid to said refrigerant liquefying means, a plurality of heat exchange pipe assemblies connected at one end to said inlet header means and connected at the opposite end to said outlet header means to pass refrigerant fluid through said assemblies in indirect heat exchange relationship with Water to be frozen, means for selectively conducting hot gaseous refrigerant from said refrigerant liquefying means to said heat exchange pipe assemblies in a reverse direction from the flow of said refrigerant to loosen the ice from the surface of said floor when the ambient temperature is above freezing, and means for selectively conducting water from said melting pit through said pipe assemblies in a reverse direction from the flow of said refrigerant to loosen the ice from the surface of said flood when the ambient temperature is below freezing.

References Cited 30,069 1/1911 Sweden.

WILLIAM J. WYE, Primary Examiner US. Cl. X.R. 

